PROJECT SUMMARY Heart failure (HF) affects more than 38 million people globally and is responsible for high rates of hospitalization and premature mortality, especially in sub-Saharan Africa. HF causes multiple debilitating and distressing symptoms. These can often be managed by patients themselves, but only when they are able to identify symptoms and select appropriate actions. Self-care, a World Health Organization-endorsed intervention for chronic conditions and a strong evidence base, is greatly underutilized in low- and middle- income countries (LMIC). In Uganda, self-care is identified as one of the greatest unmet needs among patients with HF. mHealth offers a promising platform to address this need gap in LMIC, by leveraging the widespread penetration of mobile phones to offer individualized self-care tools such as education, healthy lifestyle prompts, and decision support directly to patients with HF. Since 2016, our multidisciplinary, multi-national Research Team has been collaborating to design a locally relevant mHealth application to improve self-care among Ugandan patients with HF by adapting a smartphone-based app to the local context. Grounded in user- centered design principles, we have developed Medly Uganda and conducted usability testing of this app and an associated clinician dashboard. Medly Uganda is designed for low-cost feature phones and generates self- care instructions based on patient-reported HF symptoms. The app features multiple innovations, including full integration into a rapidly scaling, government-endorsed mHealth system and the use of both Unstructured Supplementary Service Data (USSD) and Short Messaging Service (SMS), two universal mobile phone platforms with complementary advantages. Our current proposal has a strong scientific premise and is based on the rationale that an app that engages patients with adaptive education and decision support can positively impact self-care and improve quality of life and clinical outcomes of patients with HF in LMIC. We herein propose a comprehensive evaluation of both implementation and clinical outcomes of Medly Uganda in a six month-long prospective cohort study of 72 patients and 10 clinicians at the Uganda Heart Institute in Kampala, Uganda. Alongside our two Specific Aims, we propose an innovative Research Capacity Strengthening Plan that leverages the strengths of our respective institutions. The proposed study lays the foundation for a multi-site randomized controlled trial of Medly Uganda and will generate important insights into self-care of HF as well as the application of mHealth in LMIC for chronic disease management.